摘要
Co 3 O 4 /Fe 2 O 3 p–n heterojunctions were prepared hydrothermally. • CF-5 shows a 5.6-fold response at a lower optimal temperature. • DFT reveals charge redistribution enhancing n-butanol adsorption. To selectively detect volatile organic compounds at low operating temperatures are highly desirable for industrial safety and environmental monitoring. Herein, we report the high-performance n-butanol gas sensors via interfacial engineering of Co 3 O 4 /Fe 2 O 3 p–n heterojunction composites. Hierarchical architectures composed of Fe 2 O 3 nanoparticles uniformly anchored on Co 3 O 4 nanorods were synthesized through a facile hydrothermal calcination strategy. Among the prepared samples, the optimized composite delivers a markedly enhanced sensing response of 23.08 toward 100 ppm n-butanol, representing a 5.6-fold improvement compared with pristine Co 3 O 4 , and simultaneously reducing the optimal operating temperature to 110°C. The mechanism analyses reveal pronounced interfacial charge transfer from Fe 2 O 3 to Co 3 O 4 , which induces band bending and built-in potential barriers that sensitively regulate carrier transport. The formation of heterointerfaces also significantly enriches chemisorbed oxygen species, thereby accelerating surface oxidation reactions with n-butanol molecules. As a result, the sensor exhibits outstanding selectivity against common interfering gases, fast response/recovery dynamics (42/36 s). Density functional theory calculations further elucidate that the heterojunction facilitates stronger adsorption of n-butanol and its oxidation intermediates, enhanced charge transfer, and favorable electronic-state redistribution near the Fermi level. This work highlights interfacial electronic engineering as an effective strategy for developing energy-efficient and highly reliable metal-oxide gas sensors. Download: Download high-res image (237KB) Download: Download full-size image
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